The present invention relates to a device that provides a conduit through which intra-thoracic pressures can be monitored and measured. More particularly, the present invention relates to an improved esophageal balloon catheter device that is used to obtain esophageal pressure data for evaluating, treating and diagnosing patients with various respiratory conditions and diseases.
Esophageal balloon catheter devices are commonly used as a research or clinical tool in the study of lung mechanics. Specifically, many investigators have utilized esophageal balloons to characterize the mechanical properties of the lung in both health and in disease as well as in determining the work or effort of breathing.
More recently, esophageal balloon catheter devices have been used as part of monitoring systems for diagnosing sleep disorders, the clinical management of ventilator patients, as well as a part of pulmonary function systems in the measurement of lung mechanics.
Typical esophageal balloon catheter devices employ an air-containing balloon sealed over the distal or near distal end of a catheter that transmits balloon pressure to a pressure transducer attached to the proximal end of the catheter. A pressure transducer in this context converts mechanical energy (balloon pressure) into electrical signals and units of measurement. The balloon of the catheter is usually positioned in the lower or middle third of the esophagus to monitor esophageal pressure to determine lung compliance and respiratory effort. As is known; during inhalation the pressure in the esophagus and thorax decreases, while it increases in the viscera below the diaphragm and during exhalation the pressure in the esophagus and thorax increases while it decreases in the viscera below the diaphragm.
The catheter used in these devices is sometimes constructed to be stiff and rigid enough to allow insertion through the nasal passage and down into the esophagus. A serious disadvantage of these devices is that they are uncomfortable to patients being monitored to an extent that the pressure data may be affected as well as the patient""s ability to sleep. The catheter used in these devices may also be constructed to be limp and flaccid to provide comfort during overnight esophageal pressure testing. However, the limp and flaccid nature of the catheter makes it virtually impossible to insert it into the esophagus. Accordingly, such a catheter device includes a removable stylet assembly, which consists of a wire that is inserted into the lumen of the catheter at the proximal end thereof to stiffen the catheter so that it can be inserted into the esophagus and the balloon properly positioned therein. Once the balloon of the catheter device is positioned in the esophagus, the stylet assembly needs to be removed so the pressure transducer can be attached to the proximal end of the catheter.
A major disadvantage of these devices is that it is very difficult to position the balloon correctly in the esophagus. There is an advantage in being able to monitor esophageal pressure oscillation while positioning the balloon in the esophagus. This is possible with the stiffer more rigid catheters but not with the more comfortable soft and flaccid catheters. Once the stylet is removed and the pressure transducer attached, it is often discovered that the balloon is not properly positioned in the esophagus. Because the catheter is so soft and flaccid this necessitates removing the pressure transducer and reinserting the stylet into the catheter to stiffen it so that the position of the balloon can be corrected. Unfortunately, reinserting the stylet assembly into the catheter is extremely dangerous as it can puncture the catheter and the esophagus.
Accordingly, there is a need for an improved esophageal balloon catheter device, which is soft and flaccid for comfort and yet allows for monitoring esophageal pressure oscillation to aid proper positioning of the balloon. Such a device would avoid the need for removal of the stylet to attach the pressure transducer and the subsequent risk of reinserting the stylet assembly for balloon repositioning.
An esophageal catheter device comprises a catheter with a balloon as pressure sensor affixed to an exterior surface of the catheter, and a stylet assembly including a stylet for preventing bending and flexing of the catheter during insertion in the esophagus and a port for removably attaching a pressure transducer.